This invention relates to a test head having a contact apparatus which engages an integrated circuit load board. More particularly, this invention relates to a dual-sided test head and to a floating contact surface at each side for facilitating engagement between the test head and respective load boards.
A conventional integrated circuit test system 10 is shown in FIG. 1 to include one or more test heads 12 coupled to a test system controller 14. Each test head 12 engages a single handler 16 at a load board 18. The load board 18 supports an integrated circuit device to be tested. Because the conventional test heads engage only one load board at a time, there is a great deal of down time between tests as the handler 16 repositions the load board 18 to test another integrated circuit. Accordingly, there is a need for increasing the up-time, i.e. throughput, of the test system.
One approach for increasing the system throughput is to reduce the time needed to dock the test head 12 to a handler 16. Conventional test heads 12 include a contact surface 20 which may rotate a few degrees about its center in the plane of the contactor 20 while being fixed so as to prevent movement in all other directions. As a result, substantially all the manipulation needed for docking to a handler 16 is done by manipulating the test head 12. This technique has been satisfactory for test heads with up to 256 pins. However, for test heads having 512 pins or more, the head becomes too clumsy and too heavy to manipulate freely. Accordingly, the docking time increases unsatisfactorily.
One approach for decreasing the docking time has been to provide automated manipulating devices which automate the docking process. To achieve reasonable docking times, however, the manipulator must be able to move the test head with precision within tight tolerances. Such an approach is an expensive solution. An effective less expensive solution for decreasing the docking time and increasing the system throughput is needed.